Nodal Planning Go Live Austin, TX February 3, 2011 TAC Meeting Kenneth A. Donohoo, P.E. ROS Chairperson Oncor Electric Delivery Company LLC

Nodal Planning Go Live Complete coordination of operating and planning databases is the goal Meeting all the needs of both environments Increase efficiency Original perception (2006) is that this would be handled in one database NMMS/Network Operations Model Continuous ongoing effort and coordination required to maintain both databases Process shall not create new manual workarounds Reduce possible source for errors Validation concerns Current and new NERC standards requires further operations and planning model changes to support required analysis 02/03/2011 Ken Donohoo ERCOT TAC Meeting - SCR760 & ROS Report

Nodal Planning Nodal Planning is an entirely new method to build future planning cases from operations data Many TSPs already have large existing databases of previously-vetted planning data to create future cases TSPs are a partner with ERCOT on this effort to improve the database to meet planning requirements Very complex translation of different environments Presented at 10/26/2010 NATF meeting Originally presented to 11/04/2010 TAC meeting Developing solutions and options that minimize manual workarounds and permit system-to-system porting of data 02/03/2011 Ken Donohoo ERCOT TAC Meeting - SCR760 & ROS Report

NMMS/NOM to Cases Network Long Term Topology Operations IMM Planning Model (NMMS) IMM (Software) Topology Processor (Software) Long Term Planning Models (MOD) CRR Model 02/03/2011 Ken Donohoo ERCOT TAC Meeting - SCR760 & ROS Report

SCR 760 NOM Summary Update TP/IMM to output latest PSSE version Develop process to keep current with each release Distribution substation capacitor banks Include zero impedance line ratings Associate loads and cap banks to correct CNG Additional autotransformer parameters Improve FACTS device models Assign valid PSSE IDs Include 30 degree phase shift for autotransformers Multi-Section Lines (reliability load throwover scheme) 02/03/2011 Ken Donohoo ERCOT TAC Meeting - SCR760 & ROS Report

SCR 760 Supports Nodal Protocols 3.10 Network Operations Modeling and Telemetry (1) ERCOT shall use the physical characteristics, ratings, and operational limits of all Transmission Elements of the ERCOT Transmission Grid and other information from the Transmission Service Providers (TSPs) … (2) Because the ERCOT market requires accurate modeling of Transmission Elements in order to send accurate Base Points and pricing signals to Market Participants, ERCOT shall manage the Network Operations Model. (5) ERCOT shall use consistent information within and between the various models used by ERCOT Operations, ERCOT Planning, and other workgroups in a manner that yields consistent results. For operational and planning models that are intended to represent the same system state the results should be consistent and the naming should be identical. (9) ERCOT shall update the Network Operations Model under this Section and coordinate it with the planning models for consistency to the extent applicable. 02/03/2011 Ken Donohoo ERCOT TAC Meeting - SCR760 & ROS Report

SCR 760 Supports Nodal Protocols 3.10.2 Annual Planning Model (1) For each of the next five years, ERCOT shall develop models for annual planning purposes that contain, as much as practicable, information consistent with the Network Operations Model. The “Annual Planning Model” for each of the next five years is a model of the ERCOT power system (created, approved, posted, and updated regularly by ERCOT) as it is expected to operate during peak Load conditions for the corresponding future year. (3) ERCOT shall provide model information through the use of the Electric Power Research Institute (EPRI) and North American Electric Reliability Corporation (NERC) sponsored CIM and web-based XML communications or Power System Simulator for Engineering (PSS/E) format. (5) ERCOT shall coordinate updates to the Annual Planning Model with the Network Operations Model to ensure consistency of data within and between the Annual Planning Model and Network Operations Model to the extent practicable. 02/03/2011 Ken Donohoo ERCOT TAC Meeting - SCR760 & ROS Report

SCR 760 Supports Nodal Protocols 3.10.7 ERCOT System Modeling Requirements The following subsections contain the fidelity requirements for the ERCOT Network Operations Model. 3.10.7.1 Modeling of Transmission Elements and Parameters (1) ERCOT, each TSP, and each Resource Entity shall coordinate to define each Transmission Element such that the TSP’s control center operational model and ERCOT’s Network Operations Model are consistent. 02/03/2011 Ken Donohoo ERCOT TAC Meeting - SCR760 & ROS Report

SCR 760 Supports Nodal Protocols 3.10.7.1.3 Transmission Breakers and Switches (1)ERCOT’s Network Operations Model must include all transmission breakers and switches, the operation of which may cause a change in the flow on transmission lines or Electrical Buses. Breakers and switches may only be connected to defined Electrical Buses. (3)ERCOT shall develop methods to accurately model changes in transmission line loading resulting from Load rollover schemes transferring more than ten MW. This may include modeling distribution circuit breakers, dead line sensing, or other methods that signal when the Load should be transferred from one transmission line to another transmission line. ERCOT may employ heuristic rule sets for all manual Load transfers and for automated transfers where feasible. ERCOT application software is required to model the effects of automatic or manual schemes in the field transfer Load under line outage conditions. Each TSP and as applicable, Resource Entity, shall define the Load rollover schemes under Section 3.10.7.2, Modeling of Resources and Transmission Loads, and furnish this information to ERCOT. Transmission field (right-of-way) switches must be connected to a named Electrical Bus and be included in the Network Operations Model. 02/03/2011 Ken Donohoo ERCOT TAC Meeting - SCR760 & ROS Report

SCR 760 Supports Nodal Protocols 3.10.7.1.4 Transmission and Generation Resource Step-Up Transformers (1)ERCOT shall model all transformers with a nominal low side (i.e., secondary, not tertiary) voltage above 60 kV. (3)Each TSP and Resource Entity shall provide ERCOT with information to accurately describe each transformer in the Network Operations Model… 3.10.7.1.5 Reactors, Capacitors, and other Reactive Controlled Sources (1)ERCOT shall model all controlled reactive devices. 02/03/2011 Ken Donohoo ERCOT TAC Meeting - SCR760 & ROS Report

SCR 760 Supports Nodal Protocols 3.10.7.2 Modeling of Resources and Transmission Loads (7)Each TSP shall also provide information to ERCOT describing automatic Load transfer (rollover) plans and the events that trigger which Loads are switched to other Transmission Elements on detection of Outage of a primary Transmission Element. ERCOT shall accommodate Load rollover plans in the Network Operations Model 3.10.7.4 Definition of Special Protection Systems and Remedial Action Plans (1)All Special Protection Systems (SPSs) and Remedial Action Plans (RAPs) used by ERCOT and the TSPs to maintain a secure system must be defined in the Network Operations Model. 02/03/2011 Ken Donohoo ERCOT TAC Meeting - SCR760 & ROS Report